The altered gut microbiota increases the production of molecules that can contribute to type 2 diabetes

Reviewed by Emily Henderson, B.Sc.November 18, 2020

It is bacterial changes in the gut that increase levels of imidazole propionate, the molecule that makes the body’s cells resistant to insulin in type 2 diabetes. This result emerges from a European study, MetaCardis.

The gut and its bacteria are considered important in many diseases, and several studies have shown that the gut microbiota affects the breakdown of different parts of our diet. In previous research on gut microbiota and type 2 diabetes, attention has often focused on dietary fibers that produce butyric acid and their possible effects on blood sugar regulation and insulin resistance.

In previous research by Fredrik Bäckhed, a professor of molecular medicine at the University of Gothenburg, he showed that diabetes may be linked to changes in the composition of gut bacteria, which increases the production of molecules that can contribute to the disease.

His team showed that the altered gut microbiota leads to an altered metabolism of the amino acid histidine, which in turn leads to an increase in the production of imidazole propionate, the molecule that prevents the hypoglycemic effects of insulin.

An article published in the magazine Nature Communications now confirms initial results in a large European study with 1,990 subjects, which shows that type 2 diabetes patients from Denmark, France and Germany also had increased levels of imidazole propionate in their blood.

Our study clearly shows that imidazole propionate is elevated in type 2 diabetes in other populations as well. The study also shows that imidazole propionate levels are elevated even before the diagnosis of diabetes is established, in so-called prediabetes. This could indicate that imidazole propionate may contribute to disease progression. “

Fredrik Bäckhed, Professor of Molecular Medicine, University of Gothenburg

The altered gut microbiota seen in people with type 2 diabetes has fewer species than normal glucose-tolerant individuals, which is also linked to other diseases. Researchers speculate that this leads to impaired metabolism of the amino acid histidine.

The EU-funded MetaCardis research collaboration was led by Karine Clément, Professor of Nutrition at the Sorbonne University and by Assistance Publique Hôpitaux de Paris, a director of an INSERM group in Paris.

“Interestingly, our findings suggest that it is the altered gut microbiota rather than dietary histidine intake that affects imidazole propionate levels.” She continues:

“An unhealthy diet is also associated with an increase in imidazole propionate in individuals with type 2 diabetes.”

A problem with microbiota and various disease research has been limited reproducibility. By studying the products that produce bacteria, metabolites, we focus on the function of the bacteria rather than the exact species in the gut. Fredrik Bäckhed:

“The collaboration has given us unique opportunities to confirm preliminary results that imidazole propionate may be linked to type 2 diabetes. Here we had the opportunity to analyze nearly 2,000 samples and can therefore determine that elevated levels of imidazole propionate can be linked to type 2 diabetes. Because levels are also high in prediabetes, imidazole propionate can also cause the disease in some cases, he says.